It is known that barrels and containers that are to be filled with liquids are delivered with screwed-on caps or screwed-in plugs, it thus becoming necessary to remove these closure means and to screw these on again subsequent to the filling operation. In order to ensure that when the recipient is filled, the liquid it is to be filled with runs into the filling aperture of the barrel and not beside it onto the barrel top, the barrels to be filled are aligned inside a filling facility. The manual opening and closing of the filling apertures is labor-intensive. A closing apparatus is known for the closing of the filling aperture of a barrel or the like with the aid of a device for inserting and securing a plug in the filling aperture, in which both the device for inserting the plug as well as a position determining device are mounted in such a way at a distance from one another that they are freely movable upwardly and downwardly as well as according to polar coordinates with respect to a fixed point in a plane perpendicular to the upwardly and downwardly directed movement. In addition, in this known device, a gripping device is provided in order to prevent the joint unimpeded movement of the device for inserting the plug and determining the position, and a drive means which is suitable for displacing the two devices for inserting the plug and for determining the position when the gripping device prevents the unimpeded movement, solely linearily and, of necessity, by a distance which corresponds to the distance between the two devices. This closing apparatus has very large dimensions. In order to achieve an adequate strength and the exact structural support for the mobile components, the construction is very expensive. Moreover, the power requirement for operating this closing apparatus is very great since, when performing the centering operation, the entire frame has always to be swivelled on the supporting device by one axis (DE-A-18 17 237).
According to the U.S. Pat. No. 2,983,089, a cover closing and recipient-filling apparatus is known, the construction of which is very expensive and which consequently is very awkward to operate.
Furthermore, through the DE-A-22 10 753, an apparatus for closing recipients with an excentrically arranged spout is known, the closing operation being effected with the aid of a driving mechanism, which mechanism can be displaced between a rest position and an operative position, in which a centering device carried by this driving mechanism engages into the periphery of the cover plate of the recipient which is provided with an eccentric spout in such a way that a rotatable output shaft of the driving mechanism is brought into a position that is coaxial to the recipient and is retained in the same, by a scanning device held excentrically by the shaft and which, as part of this shaft, is displaceable with the same by one circumference, the center point of which is located on the axis of the recipient and the radius of which is equal to the distance between the axis of the spout and the axis of the recipient, up to an engagement position with the spout, and which is characterized by a closing head which is maintained excentrically by the shaft in a position coaxial to the scanning facility and which is displaceable along its own axis between a rest position and an operative position, in which an engagement with the spout takes place. With the aid of this apparatus, the closing of recipients having eccentric spouts is possible, the scanning of the spout position being effected by means of a device which facilitates and expedites this scanning operation while, at the same time, it is intended to achieve with the aid of a further device that the entire operating cycle of the apparatus proceeds entirely automatically. In order to carry out all these functions, this known apparatus possesses a plurality of complicated components.
Through the DE-A-25 40 864, an apparatus for securing screw caps or screwed plugs in the filler neck apertures of barrels is known with a cantilever which, with the aid of a lifting means, is vertically displaceable and can be swivelled around a vertical axis and is provided with both a centering as well as a closing device which, by the swivelling of the cantilever, can be successively brought above the filler neck aperture of a barrel. This apparatus is constructed in such a way that the centering device is detachably connected to the cantilever by means of a receiving flange and in that, on the receiving flange, a retaining tube with joints for detector or locator fingers constructed on the tube outer wall is provided, the shanks of which being passed through openings in the retaining tube shell and can be held together by means of an elastic ring of rubber or the like and the surface sections of which that face away from the retaining tube are configured increasingly spherically to the center axis of the retaining tube with guide pilots arranged coaxially to the retaining tube, wherein, axially to the retaining tube, through an opening provided in the receiving flange, by means of a pneumatically or hydraulically functioning lifting cylinder, a centering mandrel can be displaced vertically up to the abutment on the shanks of the detector fingers and, moreover, in the closing device, a suction head for lifting the barrel closing covers by suction and a screwing head for screwing on the barrel cover plates onto the thread of the barrel filler neck provided in the filler neck aperture are disposed at the one terminal section of a receiving pipe, the other terminal section of which is rigidly connected to a drive shaft. With an apparatus constructed in this manner it is supposed to be possible, not only to place the closing cover onto the filler neck aperture and to screw the same on after a barrel has been filled, but without using the long threaded spindles or the like which are expensive to manufacture, to effect the in each case requisite movement and power transmission operations by means of hydraulically or pneumatically operating control members so that it is possible to transmit great forces even with small models.
In addition, from the U.S. Pat. No. 2,731,185, a plug screwing in apparatus with a centering and screwing head is known which consists of an outer centering ring and a screwing head which is displaceable therein against spring pressure, the same being connected by means of a drive shaft with angularly movable joints to a drive means. In this plug screwing in apparatus, the centering ring is constructed and sectionally configured in such a way that, when screwing a plug into the barrel filling aperture, it is supported on the upper and circumferentially extending rim of the filler neck and, for this reason, has to be adapted to the dimensions and the diameter of the barrel filling aperture. This centering ring cannot be used for barrel filling apertures having different dimensions. Added to this is the circumstance that the drive shaft for the screwing head is provided with angularly movable joints which consist of disk-like shaped members disposed on the extremities of the drive shaft arranged inside compartment-like bearing boxes in the form of spherical segmental coupling means with an arcuately shaped and circumferentially extending outer wall surface, wherein the spherical segmental coupling means is supported with the aid of a ball bearing on a spring-biased cylindrical shaped member in order to be able to carry out sliding movements as well. The employment of a drive shaft supported at both extremities by means of spherical segmental coupling means calls for an expensive and complicated construction which is susceptible to trouble and which does not allow the production of the plug screwing in apparatus with small dimensions. Moreover, the spherical segmental coupling means is incapable of executing large angular movements. In the event of a fouling of the bearing boxes for the spherical segmental coupling means, a serious impairment of the angular movements of the joints will ensue. In addition, a drive shaft possessing angularly movable joints at both extremities only and which is supported by means of these joints, does not possess any elevated torsional rigidity, so that when a plug is screwed into a badly fouled or rusted filling aperture of a barrel, distortions of the drive shaft may be the result.
Furthermore, through the EP-A-065180, a plug screwing in apparatus for barrels is known with a centering and screwing head, consisting of an outer centering ring and a screwing head disposed in its interior which is displaceable by spring pressure and which is connected to a drive means having angularly movable joints. This screwing in apparatus for plugs consists of a supporting frame with an upper supporting plate and a lower supporting plate, upon which a centering plate is arranged which is provided with a cruciform aperture and, in the inner wall surface of which delimiting the aparture, tapers conically in the direction of the centering and screwing head and which, at the bottom, passes into a vertical wall section, the internal diameter of the recess delimited by the wall section being larger than the diameter of the drive shaft, an accordingly sectionally configured shaped member with an outer wall surface tapering conically in the direction of the centering and screwing head is inserted into the aperture, with the shaped member carrying on its bottom end the centering ring supported on a barrel cover plate during the plug centering and screwing in operation and is connected to a section located on the centering plate with a guide plate that is retained on at least three guide bolts secured to the lower supporting plate of the supporting frame in a longitudinally displaceable manner and can be swivelled against spring pressures, and wherein the drive shaft comprises one shaft section connected to the drive means and one shaft section carrying the screwing head, both shaft sections being connected to one another by means of a double knuckle joint. With a screwing in unit for plugs constructed in this manner a fully automatic screwing in of plugs into the thread of the filler plug arranged on the filling aperture is supposed to be possible, wherein, besides an automatic centering, also a compensation for an inclination of the plug is supposed to take place. Due to the fact that this screwing in unit for plugs operates with a centering and screwing head which is provided with a conical centering surface, an inclination and thus a tilting of the screw plug is unavoidable, so that a perfect screwing on or screwing in of such screw plugs and screw caps into the thread of the barrel filler neck is not always ensured. If, due to damage, the filler neck is tilted relative to the barrel cover plate, i.e. is bent sideways, so that the longitudinal axis of the filler neck does not extend at a right angle to the plane of the barrel cover plate, then no adaptation to this special filler neck position is possible with this known screwing in unit for plugs since the centering and screwing head is incapable of adapting to this particular position despite its conical inner wall configuration.
The present invention solves the technical problem of providing a screw cap screwing in and screwing out device for barrels which not only automatically carries out a centering of the screwing head onto the filling aperture of the filler neck and a compensation if the screw cap is tilted, but which automatically aligns itself to the longitudinal axis of the barrel filler neck during the centering operation, even when the filler neck is bent sideward to the plane of the barrel cover plate or if it were to assume a tilted position, and in which the centering and screwing head is automatically returned from an inclined position into the vertical starting position and which, over and above this, renders a centering of high accuracy possible so that also screw caps provided with a fine thread can be screwed into the thread of the filler neck with a high degree of accuracy and without any difficulties.